New York's Diamond District on W. 47th St. Photo: N.Y. POST: CHAD RACHMAN

Two ninja-like robbers dressed head-to-toe in black pulled off a brazen, mid-day heist at a Diamond District store today, tying up the owner and his son and swiping $60,000 in cash and bling before fleeing, cops said.

The robbers, one of whom was armed, sprinted out of the Namat Inc. store on West 47th Street before cops were called about 2 p.m. — after the victims wiggled out of their binding in their second-story shop, cops said.

Though the cagey robbers disabled the store’s surveillance, “There are lots of video cameras on the street,” said one cop at the scene.

Merchants and shoppers were astounded at the heist at the store, which specializes in jewelry repair.

“It takes something like this to make you want to get up and do something,” said one merchant who claimed that he has been thinking about a security upgrade.

Matt Hartley, 25, with girlfriend Macey Deleon, 22, of Westchester, said they often come to Midtown to window-shop on weekends.

“The thieves must have been pros because there are cops everywhere on the street,” Hartley said. “I can’t believe they can make a clean getaway like that in Midtown.”